Efficiency is rising

Ovens are at the heart of every bakery, so any energy savings made in this area are very welcome. The government-funded Carbon Trust, which aims to reduce total carbon dioxide levels in the UK, puts it simply: "If a bakery's energy costs are 2% of all costs, and its profits are 5% of turnover, then a 10% reduction in energy costs is equivalent to a 4% profit growth."

So it's really no wonder that while the cost of electricity has continued to jump up over the past few years, so has the number of efficiency claims made by oven manufacturers. But as the range of energy-efficient ovens keeps on expanding, how can these claims be proved?

One leading industry expert says that the only fair way to measure and compare the efficiency of bakery ovens is if a standard measurement is implemented, which informs bakers of the kilowatt hour per kilogram of bread. "Obviously a standard will not be easy to implement because in order to get an accurate reading, a standard loaf of bread would have to be devised which contained not only the same ingredients but the same amount of those ingredients as well," says the expert.

In such a way, oven manufacturers that can genuinely claim that their product is energy efficient, will easily be able to prove so. At the same time, this makes it easier for bakers to make purchasing decisions based on efficiency.

"As well as the variables and complexity of setting up such a standard, oven manufacturers will probably object - as it is likely that plant bakers may put penalties in place if the ovens don't deliver the same standard of efficiency as their claims," says the expert.

But one thing is for sure, he says: while there is no standard measurement, manufacturers are having a hard time trying to decipher the different claims.

So there continues to be a raft of new product launches, all of which have a similar claim: to reduce energy usage and therefore reduce costs.

"Energy costs are one of the biggest expenses to bakers, and although there has been a dip from the recent highs, prices are only going to go one way in the long run," says David Marsh, md of Benier UK, which supplies bakery equipment to UK manufacturers, including Warburtons and Allied Bakeries.

"As a result of the increased energy costs, the amount of customers talking about energy-saving ovens has really picked up, which was not the case a few years ago," he says.

Benier is part of the Kaak Group: one of the largest manufacturers of bakery equipment. It supplies Sveba-Dahlen ovens, which boast energy efficiency. One of the ways it claims to bring savings to industrial bakers is through its patented increased baking surface (IBS) design. The design alternates the rotation of the rack every 70 seconds from clockwise to anti-clockwise. This means that the entire product is baked at the same temperature on all sides, which results in quicker, more energy-efficient and more even baking time, claims the company.

"The rotation device means that the air flow and temperature are evenly distributed throughout the oven," says Krister Magnusson, export sales director for Sveba-Dahlen. "In a traditional rotation oven, the products on the trays furthest away from the centre of rotation move in the direction of the air flow during one part of the rotation, and against it in the other part of the rotation. The problem with this kind of rotation oven is that the products always receive the same direction of airflow on the same side.

"By contrast, when baking is carried out in an oven fitted with the IBS system, the rack rotates alternately left and right, which means that the products located on the outer side of the tray receive both directions of airflow on both sides. In this way, the heat is supplied to a larger surface area and baking is quicker."

Humidity is another factor that affects the results of the baking, he adds. Sveba-Dahlen's ovens have a built-in, high-capacity steam system. Thick insulation within the walls and top, a large, double-glazed window and built-in halogen lighting are other features that make the ovens energy efficient.

Thermal oil ovens

As well as supplying Sveba-Dahlen ovens, Benier UK has also started to supply a thermal oil-heated oven, which claims to reduce energy costs by 25%, compared to a conventional convection oven. The savings are made from reduced baking times, says the company.

The thermal oven is made by the Hamburg-based company Daub, which is also part of the Kaak Group. Thermal oil is heated in a unit (a heat exchanger) outside the oven and then distributed through a series of radiator plates above and below each shelf in a rack oven. "Put very simply, it operates like a central heating system would," according to the company.

Each oven has its own pump, and precise temperature control is achieved by throttling oil from the primary heat exchanger circuit through the oven circuit. This gives an even heat throughout the oven, providing the quality usually only achieved by a deck oven.

According to Daub, bakers are assured of equal temperature distribution throughout the oven, temperatures do not drop significantly when the oven is loaded or emptied and, as the heat capacity of thermal oil is 2,600 times higher than hot air, baking times are significantly reduced.

The oven itself is easy to operate as it is fully automatic and can be used by industrial bakers for a wide range of breads, adds Marsh. He says: "While the key advantage of the Daub thermal oil system is huge energy savings, where up to 25% is typical due to shorter baking times, bakers also like the fact that there is no compromise on quality. This makes the oven ideal for both quality-orientated and cost-conscious bakers."

Elsewhere, CH Babb makes a variety of energy-saving travelling ovens and supplies Heinz, Nestlé, Cheesecake Factory and Premier Foods. The Babb oven is claimed to be able to reduce energy consumption by around 30% - and in some cases up to 50%. Recently launched into the UK, Babb claims the technology re-circulates heated air and reduces the heat lost in the flues, reducing operating costs.

Technically the design allows independent top and bottom heat control and very a tight temperature control to within one degree Celsius across a four-metre-wide belt. The tunnel oven comes in eight different types, including thermal oil, electric, radiant tube, infrared and hybrid. Each oven is custom designed and can include options such as zoned humidity control, a comprehensive electrical control system and full wash down 'high care' construction.

It's easy for manufacturers to get lost in a multitude of efficiency claims, some of which remain largely unproved. But there are several features to look out for in an oven that will help to bring down energy costs, adds Magnusson. These include: inspecting joints that should be soldered rather than screwed; using preferably mineral fibre insulation (at least 100-150mm thick); and installing bakery doors that have two sheets of glass - with the internal one coated in reflective material. All of these techniques will help to bring down bakery production costs. FM

Key Contacts​

Benier 01908 312333​

CH Babb 01296 632514​

Daub 00 49 405 476 91​

Kaak Group 00 31 315 339 111​

Sveba-Dahlen 00 46 33 15 15 22 ​